From WordNet (r) 3.0 (2006) :
sass
n 1: an impudent or insolent rejoinder; "don't give me any of
your sass" [syn: sass, sassing, backtalk, back
talk, lip, mouth]
v 1: answer back in an impudent or insolent manner; "don't sass
me!"; "The teacher punished the students who were sassing
all morning";